Single drop break-up in a Kühni column

Abstract

In order to determine breakage abilities of droplets in a Kühni column stage, an automatic device devoted to routine working and suitable for any industrial two-phase system was developed. The operating conditions were as follows: mother drop diameter, 1–4 mm; rotation speed of the impeller, 100–250 min −1; various two-phase systems were studied. Drop injection, data acquisition and data processing were achieved with a microcomputer, leading directly to the following statistical quantities: breakage probability and daughter drop size distribution. The results are discussed for the following two ternary systems recommended by the European Federation of Chemical Engineering: water-acetone-toluene and water-succinic acid-n-butanol (the aqueous phase is the continuous one). Two cases were studied: aqueous and organic phases without solute; aqueous and organic phases equilibrated with a low percentage of solute. This study affords information about drop breakage, which is necessary for establishing breakage laws. Furthermore, these laws may be introduced into a drop population balance model. In this way, it is expected that the behaviour of the dispersed phase in a Kühni column may be predicted over a wide range of operating conditions.